The invention relates to a gold-containing catalyst with porous structure that is obtainable through a process that comprises the following steps: melting together of gold and at least one less noble metal that is selected from the group consisting of silver, copper, rhodium, palladium, and platinum, and at least partial removal by dissolving the at least one less noble metal out of the starting alloy thus obtained. The catalyst has high activity and great long-term stability, despite the fact that it does not contain a support material or a compound that serves as a support material. The catalyst can be used to accelerate and/or to influence the product selectivity of oxidation and reduction reactions. The catalyst is suitable, for example, for the oxidization of carbon monoxide to carbon dioxide, which makes it usable, among other things, in a fuel cell, in particular a polymer electrolyte membrane fuel cell (PEM), for protection of the anode catalyst against blocking by carbon monoxide.